beemait



R. E. BEEMAN.

ADJUSTABLE SPARK PLUG TESTER- APPLICATION HLED OCT. 28, I918.

1 ,3 1 2 01 6 Patented Aug. 5, 1919.

I In I iew:

I'l STAT To all whom it may concern:

Be it known that l[, RALPH lE. BEEMA'N, a citizen of the United States, residing at lt finneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Adjustable Spark-Plug Testers; and 1 do hereby declare the following to be a full, clear, and exact description of the invention, such, as will enable others skilled in the art to which it appertains to make and use the same.

My invention has for its object to provide an improved spark gap tester that is readily adjustable, while the device is subject to the spark-producing current. This spark gap tester is adapted for very general use to test and measure the distance of spark gaps in' electric circuits, but will be found especially useful in testing spark plugs.

Various spark gap testers for spark plugs and the like have hitherto been produced and some thereof have been adjustable, but

in all of those that were adjustable, so far as 1 am aware, the adjusting device, that is the part necessarily engaged w1th the finger to effect the adjustment, was in circult wlth the conductors and spark gap points, so thatadjustments could not be made whilethe device was subject to electric current, without giving shocks to the person adjustments.

My invention provides an unproved de vice of the above general character, wherein the finger or thumb-engaged adjusting element, while mechanically connected to the relatively movable spark gap point, is, nevertheless, insulated therefrom so that the said adjusting element may be engaged and the adjustments accomplished without danger of shocks to the operator.

The preferred form of the device is illustrated in the accompanying drawings, wherein like characters indicate like parts throughout the several views.

Referring to thevdrawings,

Figure 1 is' a plan view of the improved device;

, Fig. 2 is a view partly in side elevat on and. partly in vertical section on the line Qr-QoflFigl; L

"Fig. 3 is a front end elevation oJLthe device Fig, 4.- is a section on the line 41-41 of Fig. 1;

making such Specification of Letters Patent.

ENT F 1cE.

1 PH E. BEEMAN, 0F MINNTEKPODHL MINNESOTA.

n-rnue 'rnsrnn Fig. 1 and v Patented Aug... .5, 1919. application filed oetober at, 11am. Serial no. scones.

' lFigf5 is a section on the line 55 of lFlg. 6 is a section on the line of Fig. 1.

This improved device, in the preferred form illustrated, comprises a handle 7 of wood or other material that is a non-conductor of electricity. This handle has two recesses 8 and 9 connected by an axial channel 10.

Two conducting contacts, shown as in the form of flat metal bars 11 and 12, are inserted through the front end of the handle 7 and extend into the recess 8 thereof, bemg, as shown, secured in position by small screws 13. The outer ends of these contact bars diverge, so that they are adapted for use in the customary way to short-circuit the spark plugs of an internal combustion engine. The contact 11, at its inner end, terminates in a relatively fixed spark gap point 141 that is located in the recess 8, approximately" at the axis of the handle 7. The relatively movable spark gap point 15 is not formed directly on the contact bar 12, although it' is in electrical contact therewith, but is formed on a secondary conduct-' ,1 ing bar 16 that slides through an eye formed in the upturned end 12 of said contact bar 12. The rear end of this bar 16 is pivoted to an adjusting element, shown as in the form of 'a solid wheel 17 located in. the re cess 9 and ivotally mounted on a pin 18 seated in t e handle 7. wheel 17 is made of insulating material, such, for example, as wood fiber or vulcan ized rubber, and is provided with a peripheral notch 17 a that afi'ords clearance for the pivoted end of the bar 16. At its free end,

This adjusting Y the bar 16 is provided with an extended arm 19, the end of which afi'ords-a pointer that cooperates with a graduated scale 20- applied on the top of the handle 7, just at the rear of the recess 8. Preferably, an insulating plate 21 is applied in the recess 8, just above the inner end of the bar 12 and between the same and the cooperating spark gap points 14 and 15. I

\ The operation of the device is substantially as follows:

The coil or rocker 17 is adapted to be oscillated by the thumb of the hand used to grip the handle 7 and by oscillations of said wheel, it is evident that-the movable spark gap point 15 may be moved toward or from the fixed spark gap point 14, at will. By noting the position of the end of the pointer 19 on the scale 20, the exact spacing of the two spark gap points may be always read. Of course, these adjustments may be produced without shocks, while the contact bars 11 and 12 are connected in the circuit, a coil of which is being tested. In the use of the device on spark plugs, these contact bars and the spark gap points will, of course, form a shunt of the ignition circuit around the .spark gap of the plug.

The spark will, of course, jump across the path of least resistance. If, now, we assume that the gap in the spark plug is th of an inch; then, if the points 14 and 15 be th of an inch or less than 'f gtll of an inch,

then a spark will also be produced between the said points 14 and 15. But, if the distance between the points 14 and 15 be materially greater than th of an inch, then no spark will be produced between the said points 14 and '15. If a spark is produced between the points 14 and 15, when the spacing between the same is more than th of an inch or greater than the known spark gap of the plug, then the operator will know that the spark is not being properly produced by the spark plug.

If it is desired to measure the maximum gap across which the spark-producingcurrent will jump, the plug can be removed or otherwise put out of action and then the contact points 14 and 15 can be gradually separated, measuring the spark to a point where it will no longer jump across the increasing spark gap distance. In the same general way, the spark-producing capacity of any currents can be measured by this device.

Of course, the thumb or other handequipped adjusting element of the device can be insulated'from the conducting elements in various different ways, the important point being that it is thus insulated. The easiest and most eflicient way of doing this, however, is to make-the wheel or rocker 3 element 17 itself, of insulating material.

Obviously, with the tester above described, the thumb can be held on the adjusting wheel and the movable spark point gradually and progressively adjusted by infinitesimal steps, while the current is producing the spark and without danger of the operator receivinga shock.

What I claim is 1. A spark gap tester comprising an insulated handle, current-conducting contacts applied to said handle, a spark gap point connected to one of said conducting contacts,

a relatively movable spark gap point electrically connected with the other conducting contact, but movable toward and from the cooperating spark gap point, and an insulated adjusting element connected to said movable spark gap point and mounted on said handle in position to be engaged by the operator.

'2. A spark gap tester comprising an insulated handle, current-conducting contacts applied to said handle, a spark gap point connected to one of said conducting contacts, a relatively movable spark gap point electrically connected with the other conducting contact, but movable toward and from the cooperating spark gap point, an insulated adjusting element connected to said movable spark gap point and mounted on said handle 1n position to be engagcd'by the operator, a'

spark gap scale on said handle, and a pointer movable with said spark gap point and cooperating with said scale.

3. A spark gap testerv comprising a handle of insulating material, two conducting contact bars applied to said handle, one of said bars terminating in a fixed spark gap point located within said handle, the other contact bar having an eye in its inner end, an adjusting wheel of insulating material mounted in said handle and having an exposed portion, a secondary contact'bar pivotally connected to said adjusting wheel, extended through the eye of the second noted contact bar and provided with a relatively movable spark gap point cooperating with said fixed spark gap point.

4. A spark gap tester comprising a handle of insulating material, two conducting contact bars applied to said handle, one of said bars terminating in a fixed spark gap point located within said handle, the other contact bar having an eye in its inner end, an adjusting wheel of insulating material mounted in said handle and having an exposed portion, a secondary contact bar pivotally connected to said adjusting wheel, extended through the eye of the second noted contact bar and provided with a relatively movable spark gap point cooperating with said fixed spark gap point, said secondary conducting bar having at its free end an extended arm terminating in a pointer, and the said handle having a scale thereon for cooperating with said pointer.

. In testimony whereof I aflix my signature in presence of two witnesses.

RALPH E. 'BEEMAN.

Witnesses:

CLARA DEMAREST, B. G. BAUMANN. 

